iPhone 6S no audio

[AGibb]

Have an iPhone 6s with previous Tristar replacement which has no audio output. Not sure if this was directly following the Tristar replacement or not. The phone boots fine and otherwise works perfectly well, but if you try to interact with any audio settings, pushing volume buttons or moving the slider in the Sounds menu the phone lags out for 10 - 20 seconds or so.

Anyone seen this before? How do I start to diagnose this? Measuring audio lines? Possible to have a partially failed chip or something nearby dislodged? Thanks,

Adam

[Jessa_the_Professa]

Take a look near the tristar chip and tell me if you see anything audio related and come back with a hypothesis of what happened here.

[AGibb]

Thanks Jessa, obviously I was eyeballing U3800 but was cautious about putting more heat in the area in case there was a known cause/solution I hadn't come across. Of course the most obvious answer is usually the right one, replaced U3800 and it's back in perfect working order

[Jessa_the_Professa]

There you go. It is all about principle of parsimony. The simplest explanation is usually the right one. Here you had heat in an area adjacent to an audio component. Which is more likely--that the phone had one problem (Tristar) and that heat and tweezers in that area damaged the adjacent component OR that this phone happened to have two completely different faults that occurred simultaneously. Both are possible, but Parsimony points to the first choice--and it was true.